Want to know how to send and receive calls and sms texts to/from cellphones (and landlines) in the U.S. for free from your mobile phone?

Steps (assuming you have an iPhone 4 or higher):
1. Sign up for Google Voice and get a standard phone number with it. Allows sms texting for free to and from that number.
2. Install the Talkatone app...this lets you place and receive calls to/from landlines and mobile phones for free over wifi or 3g/4g from the Google Voice phone number.
3. Signup for Freedompop, for the iphone sleeve. The sleeve creates a wifi hotspot to which you can connect any of your devices. They are shipping in October. They give a free 500 MB per month of data over Clearwire service, with overages after 500 MB. Clearwire service is spotty but supposedly Freedompop is going to move to Sprint 3G at some point.

Until Freedompop moves over to Sprint, you will probably want to sign up for T-Mobile pay-as-you-go for when you are out of Clearwire range. If you have an unlocked AT&T iPhone you can get the $30 per month unlimited data, sms txt, and 100 minutes of voice from T-Mobile. Currently, iphones can only get Edge on tmobile but they plan to enable hspa+ next month.